WO2024000844A1 - Lithium manganese iron phosphate preparation method and application thereof - Google Patents

Lithium manganese iron phosphate preparation method and application thereof Download PDF

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WO2024000844A1
WO2024000844A1 PCT/CN2022/119991 CN2022119991W WO2024000844A1 WO 2024000844 A1 WO2024000844 A1 WO 2024000844A1 CN 2022119991 W CN2022119991 W CN 2022119991W WO 2024000844 A1 WO2024000844 A1 WO 2024000844A1
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manganese
iron
phosphate
slurry
low
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殷磊
李长东
阮丁山
杜锐
彭卓
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广东邦普循环科技有限公司
湖南邦普循环科技有限公司
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Definitions

  • the invention belongs to the technical field of lithium ion battery cathode materials, and specifically relates to a preparation method and application of lithium manganese iron phosphate.
  • phosphate materials represented by lithium iron phosphate have the advantages of long cycle life, high safety, abundant resources, environmental friendliness, and low cost, and occupy an important position in the cathode material system of lithium-ion batteries.
  • the phosphate cathode material prepared by the phosphate method has the advantages of high compaction density, high electrochemical activity, simple preparation process, and good product batch stability.
  • lithium iron manganese phosphate Compared with lithium iron phosphate, lithium iron manganese phosphate has the advantages of high voltage platform, long cycle life, and rich resources.
  • the electrode potential of lithium iron manganese phosphate material relative to Li + /Li is 4.1V, which is higher than the 3.4V of lithium iron phosphate.
  • Lithium iron manganese phosphate retains the thermal stability of phosphate cathode materials and can greatly improve the safety of power batteries. In addition, it is low cost. Since the price of lithium iron manganese phosphate resources is relatively low, the cost can be reduced after large-scale production. However, compared with lithium iron phosphate, the electrical conductivity of lithium manganese phosphate materials is relatively poor.
  • the present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. For this reason, the present invention proposes a preparation method and application of lithium iron manganese phosphate.
  • a method for preparing lithium iron manganese phosphate which is characterized in that it includes the following steps:
  • S1 Design different ratios of manganese and iron elements, and prepare at least one high-manganese and low-iron ferromanganese phosphate and at least one high-iron and low-manganese ferromanganese phosphate according to the following methods: combine manganese source, iron source, phosphorus source, and reduce The agent and water are mixed to perform a precipitation reaction, and the resulting precipitate is heat-treated to obtain ferromanganese phosphate; wherein the high-manganese low-iron type ferromanganese phosphate is also added with a first dopant during the precipitation reaction;
  • S2 The high-manganese low-iron type ferromanganese phosphate and the high-iron low-manganese type ferromanganese phosphate are respectively made into a first slurry with a particle size D50 of 200-400nm and a second slurry with a particle size D50 of 600-800nm according to the following methods. : Mix and grind ferromanganese phosphate, lithium source, carbon source, second dopant and water to obtain slurry;
  • the molar amount of manganese in the high-manganese and low-iron ferromanganese phosphate is higher than the molar amount of iron, and the molar amount of iron in the high-iron and low-manganese ferromanganese phosphate is higher than the molar amount of manganese.
  • the Mn/Fe element molar ratio of the high-manganese low-iron ferromanganese phosphate is (1-a):a, 0.2 ⁇ a ⁇ 0.45; the high-iron low-manganese ferrophosphate
  • the Mn/Fe element molar ratio of type ferromanganese phosphate is (1-b):b, 0.55 ⁇ b ⁇ 0.8.
  • the first dopant is at least one of magnesium hydroxide, magnesium sulfate or magnesium nitrate.
  • the first dopant is magnesium sulfate. Magnesium doping can effectively broaden the lithium ion transmission channel and increase the capacity.
  • step S1 the added amount of the first dopant is 0.05-0.5%, preferably 0.3%, of the mass of the theoretically produced anhydrous high-manganese low-iron ferromanganese phosphate.
  • the reducing agent in step S1, is at least one of oxalic acid or ascorbic acid.
  • the reducing agent is oxalic acid.
  • step S1 the temperature of the heat treatment is 300-550°C, and the time of the heat treatment is 4-10 hours.
  • the phosphorus source is at least one of phosphoric acid or ammonium dihydrogen phosphate.
  • the carbon source is at least one of glucose, polyethylene glycol, sucrose, starch or cellulose.
  • the added amount of the carbon source is 5-20% by weight of ferric manganese phosphate, with a preferred value being 15%.
  • the lithium source is at least one of lithium carbonate, lithium hydroxide, lithium acetate or lithium citrate.
  • the second dopant is at least one of an aluminum compound, a titanium compound, a niobium compound or a zirconium compound.
  • the second dopant is at least one of aluminum oxide, titanium oxide, niobium pentoxide or zirconium oxide. More preferably, the second dopant is titanium oxide.
  • step S2 the addition amount of the second dopant is 0.05-0.4% by weight of ferric manganese phosphate, and the preferred value is 0.25%.
  • the molar ratio of Mn/Fe elements in the mixed slurry is 0.25-4.
  • the Mn/Fe element molar ratio in the mixed slurry is 0.5-2.0; more preferably, the Mn/Fe element molar ratio in the mixed slurry is 1.5.
  • step S3 the inlet air temperature of the spray drying is 220-260°C, and the outlet air temperature is 105-115°C.
  • step S3 the particle size D50 of the lithium iron manganese phosphate is 600-1500 nm, and the compacted density is 2.4-2.6g/cm 3 .
  • step S3 the mixing time is 30-90 minutes.
  • the protective atmosphere is a reducing atmosphere or nitrogen.
  • step S3 the sintering process is: first, the temperature is raised to 350-450°C for sintering for 2-4 hours, and then the temperature is raised to 650-750°C for 4-10 hours. Further, the heating rate is 2-4°C/min.
  • the invention also provides the application of the preparation method in preparing lithium ion batteries.
  • the present invention effectively broadens the lithium ion transmission channel, increases the capacity, and conducts nanonization and carbon coating, which can greatly improve the conductive properties and performance of lithium ferromanganese phosphate materials.
  • the present invention uses two particle size grinding methods to process two types of lithium manganese iron phosphate precursors with different Mn/Fe ratios. Among them, the small particles of high manganese and low iron type precursor mainly provide capacity performance, and the large particles of high iron and low iron type precursors mainly provide capacity performance.
  • the manganese-type precursor mainly provides the compaction density.
  • the lithium manganese iron phosphate material synthesized by combining the two precursors can not only ensure the extremely high electrochemical and conductive properties of the material, but also maintain the extremely high compaction density and processing of the material. performance.
  • the present invention can prepare lithium iron manganese phosphate cathode materials with different median voltages (3.4-3.9V) by adjusting the Mn/Fe element ratio in the formula, and has very wide applicability; in terms of technology, by adjusting the two precursors
  • the particle size of the slurry is controlled to prepare lithium iron manganese phosphate materials with high capacity and high compaction density, thereby increasing the energy density of the material and providing more performance advantages compared with ordinary lithium iron manganese phosphate.
  • the two precursors of the present invention are mixed through a liquid phase system.
  • the particle size of the slurry is the size of the primary particles. After the subsequent slurry undergoes spray drying granulation and atmosphere sintering, both the primary particles and the secondary particles of the product will grow up and are finally crushed. By controlling the particle size of the final product within a certain range, this process can make the product have excellent stability and uniformity, and more stably control the stability of the product particle size between batches.
  • Figure 1 is an SEM image of lithium iron manganese phosphate prepared in Example 1 of the present invention
  • Figure 2 is an XRD pattern of lithium iron manganese phosphate prepared in Example 1 of the present invention.
  • This example prepares lithium iron manganese phosphate.
  • the specific process is:
  • the particle size of the slurry A1 is controlled to D50 of 650nm;
  • the sintered product E1 is air-flow pulverized to prepare Mn/Fe of 6:4, D50 of 1.12um, and carbon content of 1.523% lithium iron manganese phosphate cathode material MF64-F1 with a Ti content of 1489ppm and a Mg content of 862ppm.
  • Figure 1 is an SEM image of the lithium iron manganese phosphate prepared in this embodiment. The carbon coating effect is good and the size of the particles is evenly distributed.
  • Figure 2 is an XRD pattern of lithium iron manganese phosphate prepared in this example. There are no impurity peaks in the pattern, the crystal crystallinity is intact, and the addition of Mn does not destroy the lattice structure of lithium iron phosphate.
  • This example prepares lithium iron manganese phosphate.
  • the specific process is:
  • the particle size of the slurry A2 is controlled to D50 of 650nm;
  • the sintered product E2 is airflow pulverized to prepare Mn/Fe of 4:6, D50 of 1.18um, and carbon content of 1.498%, lithium iron manganese phosphate cathode material MF46-F2 with a Ti content of 1534ppm and a Mg content of 423ppm.
  • This example prepares lithium iron manganese phosphate.
  • the specific process is:
  • the particle size of the slurry A3 is controlled to D50 of 800nm;
  • the sintered product E3 is air-pulverized to prepare Mn/Fe of 6:4, D50 of 1.25um, and carbon content of 1.524% lithium iron manganese phosphate cathode material MF64-F3 with a Ti content of 1488ppm and a Mg content of 886ppm.
  • the sintered product is airflow pulverized to prepare Mn /Fe is 6:4, D50 is 1.13um, carbon content is 1.493%, Ti content is 1564ppm, Mg content is 876ppm lithium iron manganese phosphate cathode material MF64-C1.
  • the sintered product is airflow pulverized to prepare Mn /Fe is 4:6, D50 is 1.28um, carbon content is 1.562%, Ti content is 1368ppm, Mg content is 419ppm lithium iron manganese phosphate cathode material MF46-C2.
  • a kind of lithium iron manganese phosphate was prepared in this comparative example.
  • the difference from Example 3 is that slurry A3 and slurry B3 are first spray-dried and sintered respectively, and then the two sintered products are mixed.
  • the specific process is:
  • the particle size of the slurry A3 is controlled to D50 of 800nm, and the slurry A3 is passed through a centrifugal disk spray drying equipment (the inlet air temperature is 240°C, the outlet temperature is set to 115°C) to obtain dry powder, and then the dried powder is placed Enter the atmosphere furnace, and under a nitrogen protective atmosphere, raise the temperature from normal temperature to 350°C at a heating rate of 4°C/min and keep it for 2 hours. Then continue to raise the temperature to 710°C, keep it for 10 hours, and then naturally cool it to obtain a sintered product.
  • a centrifugal disk spray drying equipment the inlet air temperature is 240°C, the outlet temperature is set to 115°C
  • the product is air-flow pulverized to obtain product one;
  • the lithium iron manganese phosphate material prepared in the Examples and Comparative Examples is slurried according to the ratio of cathode material powder: conductive agent (SP): adhesive (PVDF) of 90:5:5; the adjusted slurry is coated , develop and dry.
  • Metal lithium sheets are used as negative electrode materials, polypropylene microporous films are used as separators, and electrolytes are used to assemble them into batteries. After the battery is sealed, it is tested after resting for 2 hours. The button half-cell was tested on the blue battery test cabinet. The test voltage range was 2V ⁇ 4.3V, the cycle rate was 1C cycle, and the physical and chemical indicators such as material compaction density and resistivity were tested. The results are shown in Table 1.
  • Comparative Example 3 large and small particles are separately pulverized and then mixed.
  • the air flow pulverization process has a certain destructive effect on the carbon coating. After solid-phase mixing, the material will suffer from carbon stratification, which will cause the resistivity of the material powder to appear significantly. In addition, due to the inherent problem of poor uniformity in solid phase mixing, it will lead to uneven particle size of the material, thereby reducing the compacted density of the material.

Abstract

Disclosed in the present invention are a lithium manganese iron phosphate preparation method and an application thereof. Two lithium manganese iron phosphate precursors having different Mn/Fe ratios are respectively grinded by using two particle sizes, a small-particle high-manganese low-iron precursor mainly provides capacity performance, and a large-particle high-iron low-manganese precursor mainly provides compaction density. A lithium manganese iron phosphate material is synthesized by combining the two precursors, so that extremely high electrochemical performance and conductivity of the material can be ensured, and extremely high compaction density and processability of the material can also be maintained. The two precursors are mixed by means of a liquid phase system, the particle size of a slurry is a primary particle size, subsequently, the slurry is subjected to spray drying granulation and atmosphere sintering, and then the particle size of a final product is controlled to be within a certain range by means of crushing. The process can enable the product to have excellent stability and uniformity, and more stably control the stability in particle size between batches of products.

Description

磷酸锰铁锂的制备方法及其应用Preparation method and application of lithium iron manganese phosphate 技术领域Technical field
本发明属于锂离子电池正极材料技术领域，具体涉及一种磷酸锰铁锂的制备方法及其应用。The invention belongs to the technical field of lithium ion battery cathode materials, and specifically relates to a preparation method and application of lithium manganese iron phosphate.
背景技术Background technique
作为锂离子电池正极材料，以磷酸铁锂为代表的磷酸盐材料具有循环寿命长、安全性高、资源丰富、环境友好、成本低等优点，在锂离子电池正极材料体系中占有重要地位。其中以磷酸盐法所制备的磷酸盐正极材料，具有压实密度高，电化学活性高，制备工艺简单，产品批次稳定性好等优点。As a cathode material for lithium-ion batteries, phosphate materials represented by lithium iron phosphate have the advantages of long cycle life, high safety, abundant resources, environmental friendliness, and low cost, and occupy an important position in the cathode material system of lithium-ion batteries. Among them, the phosphate cathode material prepared by the phosphate method has the advantages of high compaction density, high electrochemical activity, simple preparation process, and good product batch stability.
相较于磷酸铁锂，磷酸锰铁锂具有电压平台高，循环寿命长，资源丰富等优点。磷酸锰铁锂材料相对于Li +/Li的电极电势为4.1V，高于磷酸铁锂的3.4V。磷酸锰铁锂保留了磷酸盐正极材料的热稳定性，能大大提高动力电池的安全性。另外是低成本，由于磷酸锰铁锂资源价格比较低，规模化生产后可以降低成本。但是同磷酸铁锂相比，磷酸锰锂的材料的导电性能相对差，所以在磷酸锰铁材料中，Mn元素含量越高，磷酸锰铁锂材料的电化学性能、导电性能、以及加工性能均会较差，极大程度上阻碍了磷酸锰铁锂材料的运用。 Compared with lithium iron phosphate, lithium iron manganese phosphate has the advantages of high voltage platform, long cycle life, and rich resources. The electrode potential of lithium iron manganese phosphate material relative to Li + /Li is 4.1V, which is higher than the 3.4V of lithium iron phosphate. Lithium iron manganese phosphate retains the thermal stability of phosphate cathode materials and can greatly improve the safety of power batteries. In addition, it is low cost. Since the price of lithium iron manganese phosphate resources is relatively low, the cost can be reduced after large-scale production. However, compared with lithium iron phosphate, the electrical conductivity of lithium manganese phosphate materials is relatively poor. Therefore, the higher the Mn element content in iron manganese phosphate materials, the poorer the electrochemical properties, conductive properties, and processing performance of lithium iron manganese phosphate materials. will be poor, which greatly hinders the application of lithium iron manganese phosphate materials.
发明内容Contents of the invention
本发明旨在至少解决上述现有技术中存在的技术问题之一。为此，本发明提出一种磷酸锰铁锂的制备方法及其应用。The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. For this reason, the present invention proposes a preparation method and application of lithium iron manganese phosphate.
根据本发明的一个方面，提出了一种磷酸锰铁锂的制备方法，其特征在于，包括以下步骤：According to one aspect of the present invention, a method for preparing lithium iron manganese phosphate is proposed, which is characterized in that it includes the following steps:
S1：设计不同锰、铁元素配比，按以下方法分别制备至少一种高锰低铁型磷酸锰铁和至少一种高铁低锰型磷酸锰铁：将锰源、铁源、磷源、还原剂和水混合进行沉淀反应，所得沉淀物进行热处理，即得磷酸锰铁；其中所述高锰低铁型磷酸锰铁在所述沉淀反应 时还加入第一掺杂剂；S1: Design different ratios of manganese and iron elements, and prepare at least one high-manganese and low-iron ferromanganese phosphate and at least one high-iron and low-manganese ferromanganese phosphate according to the following methods: combine manganese source, iron source, phosphorus source, and reduce The agent and water are mixed to perform a precipitation reaction, and the resulting precipitate is heat-treated to obtain ferromanganese phosphate; wherein the high-manganese low-iron type ferromanganese phosphate is also added with a first dopant during the precipitation reaction;
S2：所述高锰低铁型磷酸锰铁和高铁低锰型磷酸锰铁按以下方法分别制成粒径D50为200-400nm的第一浆料和粒度D50为600-800nm的第二浆料：将磷酸锰铁、锂源、碳源、第二掺杂剂和水混合研磨，即得浆料；S2: The high-manganese low-iron type ferromanganese phosphate and the high-iron low-manganese type ferromanganese phosphate are respectively made into a first slurry with a particle size D50 of 200-400nm and a second slurry with a particle size D50 of 600-800nm according to the following methods. : Mix and grind ferromanganese phosphate, lithium source, carbon source, second dopant and water to obtain slurry;
S3：将所述第一浆料和第二浆料混合，得到混合浆料，将所述混合浆料进行喷雾干燥，得到干燥粉体，将所述干燥粉体置于保护气氛下烧结，所得烧结产物经粉碎，即得所述磷酸锰铁锂。S3: Mix the first slurry and the second slurry to obtain a mixed slurry, spray-dry the mixed slurry to obtain dry powder, and sinter the dry powder under a protective atmosphere to obtain The sintered product is crushed to obtain the lithium iron manganese phosphate.
需要说明的是，高锰低铁型磷酸锰铁中锰的摩尔量高于铁的摩尔量，高铁低锰型磷酸锰铁中铁的摩尔量高于锰的摩尔量。It should be noted that the molar amount of manganese in the high-manganese and low-iron ferromanganese phosphate is higher than the molar amount of iron, and the molar amount of iron in the high-iron and low-manganese ferromanganese phosphate is higher than the molar amount of manganese.
在本发明的一些实施方式中，步骤S1中，所述高锰低铁型磷酸锰铁的Mn/Fe元素摩尔比为(1-a):a，0.2≤a≤0.45；所述高铁低锰型磷酸锰铁的Mn/Fe元素摩尔比为(1-b):b，0.55≤b≤0.8。In some embodiments of the present invention, in step S1, the Mn/Fe element molar ratio of the high-manganese low-iron ferromanganese phosphate is (1-a):a, 0.2≤a≤0.45; the high-iron low-manganese ferrophosphate The Mn/Fe element molar ratio of type ferromanganese phosphate is (1-b):b, 0.55≤b≤0.8.
在本发明的一些实施方式中，步骤S1中，所述第一掺杂剂为氢氧化镁、硫酸镁或硝酸镁中的至少一种。优选的，所述第一掺杂剂为硫酸镁。镁元素掺杂可有效拓宽锂离子传输通道，提高容量。In some embodiments of the present invention, in step S1, the first dopant is at least one of magnesium hydroxide, magnesium sulfate or magnesium nitrate. Preferably, the first dopant is magnesium sulfate. Magnesium doping can effectively broaden the lithium ion transmission channel and increase the capacity.
在本发明的一些实施方式中，步骤S1中，所述第一掺杂剂的加入量为理论产出无水高锰低铁型磷酸锰铁质量的0.05-0.5％，优选为0.3％。In some embodiments of the present invention, in step S1, the added amount of the first dopant is 0.05-0.5%, preferably 0.3%, of the mass of the theoretically produced anhydrous high-manganese low-iron ferromanganese phosphate.
在本发明的一些实施方式中，步骤S1中，所述还原剂为草酸或抗坏血酸中的至少一种。优选的，所述还原剂为草酸。In some embodiments of the present invention, in step S1, the reducing agent is at least one of oxalic acid or ascorbic acid. Preferably, the reducing agent is oxalic acid.
在本发明的一些实施方式中，步骤S1中，所述热处理的温度为300-550℃，热处理的时间为4-10h。In some embodiments of the present invention, in step S1, the temperature of the heat treatment is 300-550°C, and the time of the heat treatment is 4-10 hours.
在本发明的一些实施方式中，步骤S1中，所述磷源为磷酸或磷酸二氢铵中的至少一种。In some embodiments of the present invention, in step S1, the phosphorus source is at least one of phosphoric acid or ammonium dihydrogen phosphate.
在本发明的一些实施方式中，步骤S2中，所述碳源为葡萄糖、聚乙二醇、蔗糖、淀粉或纤维素中的至少一种。In some embodiments of the present invention, in step S2, the carbon source is at least one of glucose, polyethylene glycol, sucrose, starch or cellulose.
在本发明的一些实施方式中，步骤S2中，所述碳源的加入量为磷酸锰铁重量的5-20％，优选值为15％。In some embodiments of the present invention, in step S2, the added amount of the carbon source is 5-20% by weight of ferric manganese phosphate, with a preferred value being 15%.
在本发明的一些实施方式中，步骤S2中，所述锂源为碳酸锂、氢氧化锂、乙酸锂或柠檬酸锂中的至少一种。In some embodiments of the present invention, in step S2, the lithium source is at least one of lithium carbonate, lithium hydroxide, lithium acetate or lithium citrate.
在本发明的一些实施方式中，步骤S2中，所述第二掺杂剂为铝化合物、钛化合物、铌化合物或锆化合物中的至少一种。优选的，所述第二掺杂剂为氧化铝、氧化钛、五氧化二铌或氧化锆中的至少一种。更优选的，所述第二掺杂剂为氧化钛。In some embodiments of the present invention, in step S2, the second dopant is at least one of an aluminum compound, a titanium compound, a niobium compound or a zirconium compound. Preferably, the second dopant is at least one of aluminum oxide, titanium oxide, niobium pentoxide or zirconium oxide. More preferably, the second dopant is titanium oxide.
在本发明的一些实施方式中，步骤S2中，所述第二掺杂剂的加入量为磷酸锰铁重量的0.05-0.4％，优选值为0.25％。In some embodiments of the present invention, in step S2, the addition amount of the second dopant is 0.05-0.4% by weight of ferric manganese phosphate, and the preferred value is 0.25%.
在本发明的一些实施方式中，步骤S3中，所述混合浆料中Mn/Fe元素摩尔比为0.25-4。优选的，所述混合浆料中Mn/Fe元素摩尔比为0.5-2.0；更优选的，所述混合浆料中Mn/Fe元素摩尔比为1.5。In some embodiments of the present invention, in step S3, the molar ratio of Mn/Fe elements in the mixed slurry is 0.25-4. Preferably, the Mn/Fe element molar ratio in the mixed slurry is 0.5-2.0; more preferably, the Mn/Fe element molar ratio in the mixed slurry is 1.5.
在本发明的一些实施方式中，步骤S3中，所述喷雾干燥的进风温度为220-260℃，出风温度为105-115℃。In some embodiments of the present invention, in step S3, the inlet air temperature of the spray drying is 220-260°C, and the outlet air temperature is 105-115°C.
在本发明的一些实施方式中，步骤S3中，所述磷酸锰铁锂的粒径D50为600-1500nm，压实密度为2.4-2.6g/cm 3。 In some embodiments of the present invention, in step S3, the particle size D50 of the lithium iron manganese phosphate is 600-1500 nm, and the compacted density is 2.4-2.6g/cm 3 .
在本发明的一些实施方式中，步骤S3中，所述混合的时间为30-90min。In some embodiments of the present invention, in step S3, the mixing time is 30-90 minutes.
在本发明的一些实施方式中，步骤S3中，所述保护气氛为还原性气氛或氮气。In some embodiments of the present invention, in step S3, the protective atmosphere is a reducing atmosphere or nitrogen.
在本发明的一些实施方式中，步骤S3中，所述烧结的过程为：先升温至350-450℃下烧结2-4h，在升温至650-750℃烧结4-10h。进一步地，所述升温的速率为2-4℃/min。In some embodiments of the present invention, in step S3, the sintering process is: first, the temperature is raised to 350-450°C for sintering for 2-4 hours, and then the temperature is raised to 650-750°C for 4-10 hours. Further, the heating rate is 2-4°C/min.
本发明还提供所述的制备方法在制备锂离子电池中的应用。The invention also provides the application of the preparation method in preparing lithium ion batteries.
根据本发明的一种优选的实施方式，至少具有以下有益效果：According to a preferred embodiment of the present invention, it has at least the following beneficial effects:
1、从材料原理上讲，磷酸锰铁锂中，锰元素含量越高，材料性能越接近磷酸锰锂，反之，铁元素含量越高，材料性能越接近磷酸铁锂。本发明通过对高锰低铁型磷酸锰铁沉淀阶段掺杂元素，有效拓宽锂离子传输通道，提高容量，并进行纳米化和碳包覆，能 够极大改善磷酸锰铁锂材料的导电性能以及容量，优选掺杂镁元素；在两种磷酸锰铁混料研磨阶段掺杂铝/钛/铌/锆元素，能够有效改善产品的倍率性能；将高铁低锰磷酸锰铁制备成相对较大的颗粒材料，能够有效提高材料的压实密度，从而提升材料能量密度，更加具备性能优势。本发明采用两种粒径研磨的方式分别处理了两种不同Mn/Fe比例的磷酸锰铁锂前驱体，其中小颗粒的高锰低铁型前驱体主要提供了容量性能，大颗粒的高铁低锰型前驱体主要提供了压实密度，通过两种前驱体搭配合成的磷酸锰铁锂材料，既能保证材料极高的电化学和导电性能，又能维持材料极高的压实密度和加工性能。1. From the perspective of material principles, in lithium iron manganese phosphate, the higher the manganese content, the closer the material properties are to lithium manganese phosphate. On the contrary, the higher the iron content, the closer the material properties are to lithium iron phosphate. By doping elements during the precipitation stage of high-manganese and low-iron ferromanganese phosphate, the present invention effectively broadens the lithium ion transmission channel, increases the capacity, and conducts nanonization and carbon coating, which can greatly improve the conductive properties and performance of lithium ferromanganese phosphate materials. capacity, preferably doped with magnesium; doping aluminum/titanium/niobium/zirconium during the grinding stage of the two ferromanganese phosphate mixtures can effectively improve the rate performance of the product; prepare high-iron low-manganese ferromanganese phosphate into a relatively large Granular materials can effectively increase the compaction density of the material, thereby increasing the energy density of the material and giving it more performance advantages. The present invention uses two particle size grinding methods to process two types of lithium manganese iron phosphate precursors with different Mn/Fe ratios. Among them, the small particles of high manganese and low iron type precursor mainly provide capacity performance, and the large particles of high iron and low iron type precursors mainly provide capacity performance. The manganese-type precursor mainly provides the compaction density. The lithium manganese iron phosphate material synthesized by combining the two precursors can not only ensure the extremely high electrochemical and conductive properties of the material, but also maintain the extremely high compaction density and processing of the material. performance.
2、本发明在配方上通过Mn/Fe元素比例调整，能够制备出不同中值电压(3.4-3.9V)的磷酸锰铁锂正极材料，适用性十分广泛；在工艺上通过对两种前驱体浆料的粒径控制，制备高容量兼高压实密度的磷酸锰铁锂材料，从而提升材料的能量密度，与普通磷酸锰铁锂相比更加具备性能优势。2. The present invention can prepare lithium iron manganese phosphate cathode materials with different median voltages (3.4-3.9V) by adjusting the Mn/Fe element ratio in the formula, and has very wide applicability; in terms of technology, by adjusting the two precursors The particle size of the slurry is controlled to prepare lithium iron manganese phosphate materials with high capacity and high compaction density, thereby increasing the energy density of the material and providing more performance advantages compared with ordinary lithium iron manganese phosphate.
3、本发明两种前驱体通过液相体系混合，浆料粒度为一次颗粒尺寸，后续浆料经过喷雾干燥造粒、气氛烧结、产品的一次颗粒和二次颗粒均会长大，后通过粉碎将最终产物的粒径控制在一定范围，该工艺能够使产品具有优异的稳定性和均一性，更加稳定控制批次间产品粒度的稳定性。3. The two precursors of the present invention are mixed through a liquid phase system. The particle size of the slurry is the size of the primary particles. After the subsequent slurry undergoes spray drying granulation and atmosphere sintering, both the primary particles and the secondary particles of the product will grow up and are finally crushed. By controlling the particle size of the final product within a certain range, this process can make the product have excellent stability and uniformity, and more stably control the stability of the product particle size between batches.
附图说明Description of drawings
下面结合附图和实施例对本发明做进一步的说明，其中：The present invention will be further described below in conjunction with the accompanying drawings and examples, wherein:
图1为本发明实施例1制备的磷酸锰铁锂的SEM图；Figure 1 is an SEM image of lithium iron manganese phosphate prepared in Example 1 of the present invention;
图2为本发明实施例1制备的磷酸锰铁锂的XRD图。Figure 2 is an XRD pattern of lithium iron manganese phosphate prepared in Example 1 of the present invention.
具体实施方式Detailed ways
以下将结合实施例对本发明的构思及产生的技术效果进行清楚、完整地描述，以充分地理解本发明的目的、特征和效果。显然，所描述的实施例只是本发明的一部分实施例，而不是全部实施例，基于本发明的实施例，本领域的技术人员在不付出创造性劳动的前提下所获得的其他实施例，均属于本发明保护的范围。The concept of the present invention and the technical effects produced will be clearly and completely described below with reference to the embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without exerting creative efforts are all protection scope of the present invention.
实施例1Example 1
本实施例制备了一种磷酸锰铁锂，具体过程为：This example prepares lithium iron manganese phosphate. The specific process is:
(1)①按化学计量比Mn：Fe为8:2、(Mn+Fe)：P为1，采用电池级二氧化锰、硫酸亚铁、85％wt的工业磷酸和理论产出无水Mn 0.8Fe 0.2PO 4质量0.3％的硫酸镁，在1mol/L草酸为还原剂的水溶液中，维持温度在80℃进行沉淀反应，得到含结晶水掺镁沉淀，后经洗涤、过滤、烘干得到晶体粉末，在450℃下热处理6h，得到无定型掺镁的高锰低铁型磷酸锰铁粉末。②按化学计量比Mn：Fe为2：8、(Mn+Fe)：P为1，采用电池级二氧化锰、硫酸亚铁、85％wt的工业磷酸，在草酸为还原剂下的水溶液中，维持温度在80℃进行沉淀反应，得到含结晶水沉淀，后经洗涤、过滤、烘干得到晶体粉末，在450℃下热处理6h，得到无定型高铁低锰型磷酸锰铁粉末； (1) ①According to the stoichiometric ratio of Mn: Fe as 8:2 and (Mn+Fe): P as 1, use battery grade manganese dioxide, ferrous sulfate, 85%wt industrial phosphoric acid and theoretical output of anhydrous Mn 0.8 Fe 0.2 PO 4 0.3% magnesium sulfate by mass, in an aqueous solution with 1 mol/L oxalic acid as the reducing agent, maintain the temperature at 80°C to perform a precipitation reaction, and obtain a precipitate containing crystal water mixed with magnesium, which is then washed, filtered, and dried to obtain The crystal powder is heat-treated at 450°C for 6 hours to obtain amorphous magnesium-doped high-manganese and low-iron ferromanganese phosphate powder. ②According to the stoichiometric ratio of Mn:Fe: 2:8, (Mn+Fe):P: 1, use battery grade manganese dioxide, ferrous sulfate, 85% wt industrial phosphoric acid, in an aqueous solution with oxalic acid as the reducing agent , maintain the temperature at 80°C to perform a precipitation reaction to obtain a precipitate containing crystal water, which is then washed, filtered, and dried to obtain a crystal powder, which is heat treated at 450°C for 6 hours to obtain amorphous high-iron low-manganese ferromanganese phosphate powder;
(2)对于两种不同Mn/Fe的磷酸锰铁粉末分别采用不同的工艺处理：①对于高铁低锰型磷酸锰铁粉末：按照化学计量比Li：(Mn+Fe)为1.025:1，将高铁低锰型磷酸锰铁粉末与电池级碳酸锂进行混合，再加入高铁低锰型磷酸锰铁粉末重量15％的葡萄糖、0.25％的二氧化钛，按照35％的固含量与纯水进行混合研磨，将该浆料A1的粒度控制在D50为650nm；②对于高锰低铁型磷酸锰铁粉末：按照化学计量比Li：(Mn+Fe)为1.025:1，将高锰低铁型磷酸锰铁粉末与电池级碳酸锂进行混合，再加入高锰低铁型磷酸锰铁粉末重量15％的葡萄碳、0.25％的二氧化钛，按照35％的固含量与纯水进行混合研磨，将该浆料B1的粒度控制在D50为350nm；(2) Different processes are used for two different Mn/Fe ferromanganese phosphate powders: ① For high iron and low manganese ferromanganese phosphate powder: according to the stoichiometric ratio Li: (Mn+Fe) is 1.025:1, Mix high-iron low-manganese ferromanganese phosphate powder with battery-grade lithium carbonate, then add 15% glucose and 0.25% titanium dioxide by weight of high-iron low-manganese ferromanganese phosphate powder, mix and grind with pure water to a solid content of 35%. The particle size of the slurry A1 is controlled to D50 of 650nm; ② For high manganese and low iron ferromanganese phosphate powder: According to the stoichiometric ratio Li: (Mn+Fe) is 1.025:1, the high manganese and low iron ferromanganese phosphate powder is The powder is mixed with battery-grade lithium carbonate, then 15% grape carbon and 0.25% titanium dioxide by weight of high-manganese low-iron ferromanganese phosphate powder are added, and the solid content is mixed and ground with pure water to 35%, and the slurry B1 is The particle size is controlled at D50 of 350nm;
(3)将上述浆料A1、浆料B1按照1：2浆料质量比进行混合，分散搅拌60min后得到混合浆料C1，将混合浆料C1通过离心盘喷雾干燥设备(进风温度为240℃，出风温度设置为115℃)得到干燥粉体D1，随后将干燥粉体D1放入气氛炉，在氮气保护气氛下，从常温下按照4℃/min的升温速率，升温至350℃保温2h，后续继续升温至710℃，保温10h，再进行自然冷却，得到烧结产物E1，将烧结产物E1进行气流粉碎，即可制备得到Mn/Fe为6:4、D50为1.12um、碳含量为1.523％、Ti含量为1489ppm、Mg含量为862ppm的磷酸铁锰锂正极材料MF64-F1。(3) Mix the above slurry A1 and slurry B1 according to the slurry mass ratio of 1:2, disperse and stir for 60 minutes to obtain the mixed slurry C1, and pass the mixed slurry C1 through the centrifugal disk spray drying equipment (the inlet air temperature is 240 ℃, the outlet temperature is set to 115 ℃) to obtain the dry powder D1, and then put the dry powder D1 into the atmosphere furnace, and in a nitrogen protective atmosphere, heat it from normal temperature to 350 ℃ at a heating rate of 4 ℃/min and keep it warm 2h, then continue to raise the temperature to 710°C, keep the temperature for 10h, and then perform natural cooling to obtain the sintered product E1. The sintered product E1 is air-flow pulverized to prepare Mn/Fe of 6:4, D50 of 1.12um, and carbon content of 1.523% lithium iron manganese phosphate cathode material MF64-F1 with a Ti content of 1489ppm and a Mg content of 862ppm.
图1为本实施例制备的磷酸锰铁锂的SEM图，其碳包覆效果较好，大小颗粒分布均匀。图2本实施例制备的磷酸锰铁锂的XRD图，图谱中无杂质峰，晶体结晶度完好， Mn加入并没有破坏磷酸铁锂的晶格结构。Figure 1 is an SEM image of the lithium iron manganese phosphate prepared in this embodiment. The carbon coating effect is good and the size of the particles is evenly distributed. Figure 2 is an XRD pattern of lithium iron manganese phosphate prepared in this example. There are no impurity peaks in the pattern, the crystal crystallinity is intact, and the addition of Mn does not destroy the lattice structure of lithium iron phosphate.
实施例2Example 2
本实施例制备了一种磷酸锰铁锂，具体过程为：This example prepares lithium iron manganese phosphate. The specific process is:
(1)①按化学计量比Mn：Fe为8:2、(Mn+Fe)：P为1，采用硫酸锰、硫酸亚铁、85％wt的工业磷酸和理论产出无水Mn 0.8Fe 0.2PO 4质量0.3％的硫酸镁，在1mol/L草酸为还原剂的水溶液中，维持温度在80℃进行沉淀反应，得到含结晶水掺镁沉淀，后经洗涤、过滤、烘干得到晶体粉末，在450℃下热处理6h，得到无定型掺镁的高锰低铁型磷酸锰铁粉末。②按化学计量比Mn：Fe为2：8、(Mn+Fe)：P为1，采用电池级二氧化锰、硫酸亚铁、85％wt的工业磷酸，在草酸为还原剂下的水溶液中，维持温度在80℃进行沉淀反应，得到含结晶水沉淀，后经洗涤、过滤、烘干得到晶体粉末，在450℃下热处理6h，得到无定型高铁低锰型磷酸锰铁粉末； (1) ①According to the stoichiometric ratio of Mn: Fe as 8:2 and (Mn+Fe): P as 1, use manganese sulfate, ferrous sulfate, 85% wt of industrial phosphoric acid and the theoretical output of anhydrous Mn 0.8 Fe 0.2 PO 4 mass 0.3% magnesium sulfate, in an aqueous solution with 1 mol/L oxalic acid as the reducing agent, maintain the temperature at 80°C to perform a precipitation reaction, and obtain a precipitate containing crystal water mixed with magnesium, which is then washed, filtered, and dried to obtain a crystal powder. After heat treatment at 450°C for 6 hours, amorphous magnesium-doped high-manganese and low-iron ferromanganese phosphate powder was obtained. ②According to the stoichiometric ratio of Mn:Fe: 2:8, (Mn+Fe):P: 1, use battery grade manganese dioxide, ferrous sulfate, 85% wt industrial phosphoric acid, in an aqueous solution with oxalic acid as the reducing agent , maintain the temperature at 80°C to perform a precipitation reaction to obtain a precipitate containing crystal water, which is then washed, filtered, and dried to obtain a crystal powder, which is heat treated at 450°C for 6 hours to obtain amorphous high-iron low-manganese ferromanganese phosphate powder;
(2)对于两种不同Mn/Fe的磷酸锰铁粉末分别采用不同的工艺处理：①对于高铁低锰型磷酸锰铁粉末：按照化学计量比Li：(Mn+Fe)为1.025:1，将高铁低锰型磷酸锰铁粉末与电池级碳酸锂进行混合，再加入高铁低锰型磷酸锰铁粉末重量15％的葡萄糖、0.25％的二氧化钛，按照35％的固含量与纯水进行混合研磨，将该浆料A2的粒度控制在D50为650nm；②对于高锰低铁型磷酸锰铁粉末：按照化学计量比Li：(Mn+Fe)为1.025:1，将高锰低铁型磷酸锰铁粉末与电池级碳酸锂进行混合，再加入高锰低铁型磷酸锰铁粉末重量15％的葡萄碳、0.25％的二氧化钛，按照35％的固含量与纯水进行混合研磨，将该浆料B2的粒度控制在D50为350nm；(2) Different processes are used for two different Mn/Fe ferromanganese phosphate powders: ① For high iron and low manganese ferromanganese phosphate powder: according to the stoichiometric ratio Li: (Mn+Fe) is 1.025:1, Mix high-iron low-manganese ferromanganese phosphate powder with battery-grade lithium carbonate, then add 15% glucose and 0.25% titanium dioxide by weight of high-iron low-manganese ferromanganese phosphate powder, mix and grind with pure water to a solid content of 35%. The particle size of the slurry A2 is controlled to D50 of 650nm; ② For high manganese and low iron ferromanganese phosphate powder: According to the stoichiometric ratio Li: (Mn+Fe) is 1.025:1, the high manganese and low iron ferromanganese phosphate powder is The powder is mixed with battery-grade lithium carbonate, then 15% grape carbon and 0.25% titanium dioxide by weight of high-manganese low-iron ferromanganese phosphate powder are added, mixed and ground to a solid content of 35% with pure water, and the slurry B2 The particle size is controlled at D50 of 350nm;
(3)将上述浆料A2、浆料B2按照2：1浆料质量比进行混合，分散搅拌60min后得到混合浆料C2，将混合浆料C2通过离心盘喷雾干燥设备(进风温度为240℃，出风温度设置为115℃)得到干燥粉体D2，随后将干燥粉体D2放入气氛炉，在氮气保护气氛下，从常温下按照4℃/min的升温速率，升温至350℃保温2h，后续继续升温至710℃，保温10h，再进行自然冷却，得到烧结产物E2，将烧结产物E2进行气流粉碎，即可制备得到Mn/Fe为4:6、D50为1.18um、碳含量为1.498％、Ti含量为1534ppm、Mg含量为423ppm的磷酸铁锰锂正极材料MF46-F2。(3) Mix the above slurry A2 and slurry B2 according to the slurry mass ratio of 2:1, disperse and stir for 60 minutes to obtain the mixed slurry C2, and pass the mixed slurry C2 through the centrifugal disk spray drying equipment (the inlet air temperature is 240 ℃, the air outlet temperature is set to 115 ℃) to obtain the dry powder D2, and then put the dry powder D2 into the atmosphere furnace. Under a nitrogen protective atmosphere, the temperature is raised from normal temperature to 350 ℃ at a heating rate of 4 ℃/min. 2h, then continue to raise the temperature to 710°C, keep the temperature for 10h, and then perform natural cooling to obtain the sintered product E2. The sintered product E2 is airflow pulverized to prepare Mn/Fe of 4:6, D50 of 1.18um, and carbon content of 1.498%, lithium iron manganese phosphate cathode material MF46-F2 with a Ti content of 1534ppm and a Mg content of 423ppm.
实施例3Example 3
本实施例制备了一种磷酸锰铁锂，具体过程为：This example prepares lithium iron manganese phosphate. The specific process is:
(1)①按化学计量比Mn：Fe为8:2、(Mn+Fe)：P为1，采用电池级二氧化锰、硫酸亚铁、85％wt的工业磷酸和理论产出无水Mn 0.8Fe 0.2PO 4质量0.3％的硫酸镁，在1mol/L草酸为还原剂的水溶液中，维持温度在80℃进行沉淀反应，得到含结晶水掺镁沉淀，后经洗涤、过滤、烘干得到晶体粉末，在450℃下热处理6h，得到无定型掺镁的高锰低铁型磷酸锰铁粉末。②按化学计量比Mn：Fe为2：8、(Mn+Fe)：P为1，采用电池级二氧化锰、硫酸亚铁、85％wt的工业磷酸，在草酸为还原剂下的水溶液中，维持温度在80℃进行沉淀反应，得到含结晶水沉淀，后经洗涤、过滤、烘干得到晶体粉末，在450℃下热处理6h，得到无定型高铁低锰型磷酸锰铁粉末； (1) ①According to the stoichiometric ratio of Mn: Fe as 8:2 and (Mn+Fe): P as 1, use battery grade manganese dioxide, ferrous sulfate, 85%wt industrial phosphoric acid and theoretical output of anhydrous Mn 0.8 Fe 0.2 PO 4 0.3% magnesium sulfate by mass, in an aqueous solution with 1 mol/L oxalic acid as the reducing agent, maintain the temperature at 80°C to perform a precipitation reaction, and obtain a precipitate containing crystal water mixed with magnesium, which is then washed, filtered, and dried to obtain The crystal powder is heat-treated at 450°C for 6 hours to obtain amorphous magnesium-doped high-manganese and low-iron ferromanganese phosphate powder. ②According to the stoichiometric ratio of Mn:Fe: 2:8, (Mn+Fe):P: 1, use battery grade manganese dioxide, ferrous sulfate, 85% wt industrial phosphoric acid, in an aqueous solution with oxalic acid as the reducing agent , maintain the temperature at 80°C to perform a precipitation reaction to obtain a precipitate containing crystal water, which is then washed, filtered, and dried to obtain a crystal powder, which is heat treated at 450°C for 6 hours to obtain amorphous high-iron low-manganese ferromanganese phosphate powder;
(2)对于两种不同Mn/Fe的磷酸锰铁粉末分别采用不同的工艺处理：①对于高铁低锰型磷酸锰铁粉末：按照化学计量比Li：(Mn+Fe)为1.025:1，将高铁低锰型磷酸锰铁粉末与电池级碳酸锂进行混合，再加入高铁低锰型磷酸锰铁粉末重量15％的葡萄糖、0.25％的二氧化钛，按照35％的固含量与纯水进行混合研磨，将该浆料A3的粒度控制在D50为800nm；②对于高锰低铁型磷酸锰铁粉末：按照化学计量比Li：(Mn+Fe)为1.025:1，将高锰低铁型磷酸锰铁粉末与电池级碳酸锂进行混合，再加入高锰低铁型磷酸锰铁粉末重量15％的葡萄碳、0.25％的二氧化钛，按照35％的固含量与纯水进行混合研磨，将该浆料B3的粒度控制在D50为300nm；(2) Different processes are used for two different Mn/Fe ferromanganese phosphate powders: ① For high iron and low manganese ferromanganese phosphate powder: according to the stoichiometric ratio Li: (Mn+Fe) is 1.025:1, Mix high-iron low-manganese ferromanganese phosphate powder with battery-grade lithium carbonate, then add 15% glucose and 0.25% titanium dioxide by weight of high-iron low-manganese ferromanganese phosphate powder, mix and grind with pure water to a solid content of 35%. The particle size of the slurry A3 is controlled to D50 of 800nm; ② For high manganese and low iron ferromanganese phosphate powder: According to the stoichiometric ratio Li: (Mn+Fe) is 1.025:1, the high manganese and low iron ferromanganese phosphate powder is The powder is mixed with battery-grade lithium carbonate, then 15% grape carbon and 0.25% titanium dioxide by weight of high-manganese low-iron ferromanganese phosphate powder are added, mixed and ground to a solid content of 35% with pure water, and the slurry B3 The particle size is controlled at D50 of 300nm;
(3)将上述浆料A3、浆料B3按照1：2浆料质量比进行混合，分散搅拌60min后得到混合浆料C3，将混合浆料C3通过离心盘喷雾干燥设备(进风温度为240℃，出风温度设置为115℃)得到干燥粉体D3，随后将干燥粉体D3放入气氛炉，在氮气保护气氛下，从常温下按照4℃/min的升温速率，升温至350℃保温2h，后续继续升温至710℃，保温10h，再进行自然冷却，得到烧结产物E3，将烧结产物E3进行气流粉碎，即可制备得到Mn/Fe为6:4、D50为1.25um、碳含量为1.524％、Ti含量为1488ppm、Mg含量为886ppm的磷酸铁锰锂正极材料MF64-F3。(3) Mix the above slurry A3 and slurry B3 according to the slurry mass ratio of 1:2, disperse and stir for 60 minutes to obtain the mixed slurry C3, and pass the mixed slurry C3 through the centrifugal disk spray drying equipment (the inlet air temperature is 240 ℃, the outlet temperature is set to 115 ℃) to obtain the dry powder D3, and then put the dry powder D3 into the atmosphere furnace, and in a nitrogen protective atmosphere, heat it up from normal temperature to 350 ℃ at a heating rate of 4 ℃/min and keep it warm 2h, then continue to raise the temperature to 710°C, keep the temperature for 10h, and then perform natural cooling to obtain the sintered product E3. The sintered product E3 is air-pulverized to prepare Mn/Fe of 6:4, D50 of 1.25um, and carbon content of 1.524% lithium iron manganese phosphate cathode material MF64-F3 with a Ti content of 1488ppm and a Mg content of 886ppm.
对比例1Comparative example 1
本对比例制备了一种磷酸锰铁锂，具体过程为：In this comparative example, a lithium iron manganese phosphate was prepared. The specific process is:
(1)按化学计量比Mn：Fe为6:4、(Mn+Fe)：P为1，采用电池级二氧化锰、硫酸亚铁、85％wt的工业磷酸和理论产出无水Mn 0.6Fe 0.4PO 4质量0.2％的硫酸镁(与实施例1掺入量一致)，在1mol/L草酸为还原剂的水溶液中，维持温度在80℃进行沉淀反应，得到含结晶水掺镁沉淀，后经洗涤、过滤、烘干得到晶体粉末，在450℃下热处理6h，得到无定型磷酸锰铁粉末； (1) According to the stoichiometric ratio of Mn: Fe as 6:4 and (Mn+Fe): P as 1, battery grade manganese dioxide, ferrous sulfate, 85% wt industrial phosphoric acid and theoretical output of anhydrous Mn 0.6 are used Fe 0.4 PO 4 mass 0.2% magnesium sulfate (the dosage is the same as in Example 1), in an aqueous solution with 1 mol/L oxalic acid as the reducing agent, maintain the temperature at 80°C to perform a precipitation reaction, and obtain a crystal water-containing magnesium-containing precipitate, Afterwards, the crystal powder is obtained by washing, filtering and drying, and then heat-treated at 450°C for 6 hours to obtain amorphous ferromanganese phosphate powder;
(2)按照化学计量比Li：(Mn+Fe)为1.025:1，将磷酸锰铁粉末与电池级碳酸锂进行混合，再加入磷酸锰铁粉末重量15％的葡萄糖、0.25％的二氧化钛，按照35％的固含量与纯水进行混合研磨，将该浆料Z1的粒度控制在D50为350nm；(2) According to the stoichiometric ratio Li: (Mn+Fe) of 1.025:1, mix ferromanganese phosphate powder and battery grade lithium carbonate, then add 15% glucose and 0.25% titanium dioxide by weight of ferromanganese phosphate powder, according to Mix and grind 35% solid content with pure water, and control the particle size of the slurry Z1 to D50 of 350nm;
(3)将浆料Z1通过离心盘喷雾干燥设备(进风温度为240℃，出风温度设置为115℃)得到干燥粉体，随后将干燥粉体放入气氛炉，在氮气保护气氛下，从常温下按照4℃/min的升温速率，升温至350℃保温2h，后续继续升温至710℃，保温10h，再进行自然冷却，得到烧结产物，将烧结产物进行气流粉碎，即可制备得到Mn/Fe为6:4、D50为1.13um、碳含量为1.493％、Ti含量为1564ppm、Mg含量为876ppm的磷酸铁锰锂正极材料MF64-C1。(3) Pass the slurry Z1 through the centrifugal disk spray drying equipment (the inlet air temperature is 240°C, the outlet temperature is set to 115°C) to obtain dry powder, and then put the dried powder into the atmosphere furnace, under a nitrogen protective atmosphere, From normal temperature, the temperature is raised to 350°C at a heating rate of 4°C/min and kept for 2 hours. Then, the temperature is continued to be raised to 710°C, kept for 10 hours, and then naturally cooled to obtain a sintered product. The sintered product is airflow pulverized to prepare Mn /Fe is 6:4, D50 is 1.13um, carbon content is 1.493%, Ti content is 1564ppm, Mg content is 876ppm lithium iron manganese phosphate cathode material MF64-C1.
对比例2Comparative example 2
本对比例制备了一种磷酸锰铁锂，具体过程为：In this comparative example, a lithium iron manganese phosphate was prepared. The specific process is:
(1)按化学计量比Mn：Fe为4:6、(Mn+Fe)：P为1，采用电池级硫酸锰、硫酸亚铁、85％wt的工业磷酸和理论产出无水Mn 0.4Fe 0.6PO 4质量0.1％的硫酸镁(与实施例2掺入量一致)，在1mol/L草酸为还原剂的水溶液中，维持温度在80℃进行沉淀反应，得到含结晶水掺镁沉淀，后经洗涤、过滤、烘干得到晶体粉末，在450℃下热处理6h，得到无定型磷酸锰铁粉末； (1) According to the stoichiometric ratio of Mn: Fe is 4:6, (Mn+Fe): P is 1, using battery grade manganese sulfate, ferrous sulfate, 85% wt industrial phosphoric acid and theoretical output anhydrous Mn 0.4 Fe 0.6 PO 4 mass 0.1% magnesium sulfate (the dosage is consistent with that of Example 2), in an aqueous solution with 1 mol/L oxalic acid as the reducing agent, maintain the temperature at 80°C to perform a precipitation reaction, and obtain a crystallized water-doped magnesium precipitate. After washing, filtering, and drying, the crystal powder is obtained, and then heat-treated at 450°C for 6 hours to obtain amorphous ferromanganese phosphate powder;
(2)按照化学计量比Li：(Mn+Fe)为1.025:1，将磷酸锰铁粉末与电池级碳酸锂进行混合，再加入磷酸锰铁粉末重量15％的葡萄糖、0.25％的二氧化钛，按照35％的固含量与纯水进行混合研磨，将该浆料Z2的粒度控制在D50为350nm；(2) According to the stoichiometric ratio Li: (Mn+Fe) of 1.025:1, mix ferromanganese phosphate powder and battery grade lithium carbonate, then add 15% glucose and 0.25% titanium dioxide by weight of ferromanganese phosphate powder, according to Mix and grind 35% solid content with pure water, and control the particle size of the slurry Z2 to D50 of 350nm;
(3)将浆料Z2通过离心盘喷雾干燥设备(进风温度为240℃，出风温度设置为115℃) 得到干燥粉体，随后将干燥粉体放入气氛炉，在氮气保护气氛下，从常温下按照4℃/min的升温速率，升温至350℃保温2h，后续继续升温至710℃，保温10h，再进行自然冷却，得到烧结产物，将烧结产物进行气流粉碎，即可制备得到Mn/Fe为4:6、D50为1.28um、碳含量为1.562％、Ti含量为1368ppm、Mg含量为419ppm的磷酸铁锰锂正极材料MF46-C2。(3) Pass the slurry Z2 through the centrifugal disk spray drying equipment (the inlet air temperature is 240°C, the outlet temperature is set to 115°C) to obtain dry powder, and then put the dried powder into the atmosphere furnace, under a nitrogen protective atmosphere, From normal temperature, the temperature is raised to 350°C at a heating rate of 4°C/min and kept for 2 hours. Then, the temperature is continued to be raised to 710°C, kept for 10 hours, and then naturally cooled to obtain a sintered product. The sintered product is airflow pulverized to prepare Mn /Fe is 4:6, D50 is 1.28um, carbon content is 1.562%, Ti content is 1368ppm, Mg content is 419ppm lithium iron manganese phosphate cathode material MF46-C2.
对比例3Comparative example 3
本对比例制备了一种磷酸锰铁锂，与实施例3的区别在于，浆料A3、浆料B3先各自喷雾干燥和烧结，再将两种烧结产物混合，具体过程为：A kind of lithium iron manganese phosphate was prepared in this comparative example. The difference from Example 3 is that slurry A3 and slurry B3 are first spray-dried and sintered respectively, and then the two sintered products are mixed. The specific process is:
(1)①按化学计量比Mn：Fe为8:2、(Mn+Fe)：P为1，采用电池级二氧化锰、硫酸亚铁、85％wt的工业磷酸和理论产出无水Mn 0.8Fe 0.2PO 4质量0.3％的硫酸镁，在1mol/L草酸为还原剂的水溶液中，维持温度在80℃进行沉淀反应，得到含结晶水掺镁沉淀，后经洗涤、过滤、烘干得到晶体粉末，在450℃下热处理6h，得到无定型掺镁的高锰低铁型磷酸锰铁粉末。②按化学计量比Mn：Fe为2：8、(Mn+Fe)：P为1，采用电池级二氧化锰、硫酸亚铁、85％wt的工业磷酸，在草酸为还原剂下的水溶液中，维持温度在80℃进行沉淀反应，得到含结晶水沉淀，后经洗涤、过滤、烘干得到晶体粉末，在450℃下热处理6h，得到无定型高铁低锰型磷酸锰铁粉末； (1) ①According to the stoichiometric ratio of Mn: Fe as 8:2 and (Mn+Fe): P as 1, use battery grade manganese dioxide, ferrous sulfate, 85%wt industrial phosphoric acid and theoretical output of anhydrous Mn 0.8 Fe 0.2 PO 4 0.3% magnesium sulfate by mass, in an aqueous solution with 1 mol/L oxalic acid as the reducing agent, maintain the temperature at 80°C to perform a precipitation reaction, and obtain a precipitate containing crystal water mixed with magnesium, which is then washed, filtered, and dried to obtain The crystal powder is heat-treated at 450°C for 6 hours to obtain amorphous magnesium-doped high-manganese and low-iron ferromanganese phosphate powder. ②According to the stoichiometric ratio of Mn:Fe: 2:8, (Mn+Fe):P: 1, use battery grade manganese dioxide, ferrous sulfate, 85% wt industrial phosphoric acid, in an aqueous solution with oxalic acid as the reducing agent , maintain the temperature at 80°C to perform a precipitation reaction to obtain a precipitate containing crystal water, which is then washed, filtered, and dried to obtain a crystal powder, which is heat treated at 450°C for 6 hours to obtain amorphous high-iron low-manganese ferromanganese phosphate powder;
(2)对于两种不同Mn/Fe的磷酸锰铁粉末分别采用不同的工艺处理：①对于高铁低锰型磷酸锰铁粉末：按照化学计量比Li：(Mn+Fe)为1.025:1，将高铁低锰型磷酸锰铁粉末与电池级碳酸锂进行混合，再加入高铁低锰型磷酸锰铁粉末重量15％的葡萄糖、0.25％的二氧化钛，按照35％的固含量与纯水进行混合研磨，将该浆料A3的粒度控制在D50为800nm，将浆料A3通过离心盘喷雾干燥设备(进风温度为240℃，出风温度设置为115℃)得到干燥粉体，随后将干燥粉体放入气氛炉，在氮气保护气氛下，从常温下按照4℃/min的升温速率，升温至350℃保温2h，后续继续升温至710℃，保温10h，再进行自然冷却，得到烧结产物，将烧结产物进行气流粉碎得到产物一；②对于高锰低铁型磷酸锰铁粉末：按照化学计量比Li：(Mn+Fe)为1.025:1，将高锰低铁型磷酸锰铁粉末与电池级碳酸锂进行混合，再加入高锰低铁型磷酸锰铁粉末重量15％的葡萄碳、 0.25％的二氧化钛，按照35％的固含量与纯水进行混合研磨，将该浆料B3的粒度控制在D50为300nm，将浆料B3通过离心盘喷雾干燥设备(进风温度为240℃，出风温度设置为115℃)得到干燥粉体，随后将干燥粉体放入气氛炉，在氮气保护气氛下，从常温下按照4℃/min的升温速率，升温至350℃保温2h，后续继续升温至710℃，保温10h，再进行自然冷却，得到烧结产物，将烧结产物进行气流粉碎得到产物二；(2) Different processes are used for two different Mn/Fe ferromanganese phosphate powders: ① For high iron and low manganese ferromanganese phosphate powder: according to the stoichiometric ratio Li: (Mn+Fe) is 1.025:1, Mix high-iron low-manganese ferromanganese phosphate powder with battery-grade lithium carbonate, then add 15% glucose and 0.25% titanium dioxide by weight of high-iron low-manganese ferromanganese phosphate powder, mix and grind with pure water to a solid content of 35%. The particle size of the slurry A3 is controlled to D50 of 800nm, and the slurry A3 is passed through a centrifugal disk spray drying equipment (the inlet air temperature is 240°C, the outlet temperature is set to 115°C) to obtain dry powder, and then the dried powder is placed Enter the atmosphere furnace, and under a nitrogen protective atmosphere, raise the temperature from normal temperature to 350°C at a heating rate of 4°C/min and keep it for 2 hours. Then continue to raise the temperature to 710°C, keep it for 10 hours, and then naturally cool it to obtain a sintered product. The product is air-flow pulverized to obtain product one; ② For high manganese and low iron ferromanganese phosphate powder: according to the stoichiometric ratio Li: (Mn+Fe) is 1.025:1, combine high manganese and low iron ferromanganese phosphate powder with battery grade carbonic acid Mix lithium, then add 15% grape carbon and 0.25% titanium dioxide by weight of high manganese and low iron ferromanganese phosphate powder, mix and grind with pure water according to 35% solid content, and control the particle size of slurry B3 to D50 is 300nm, pass the slurry B3 through the centrifugal disk spray drying equipment (the inlet air temperature is 240°C, the outlet temperature is set to 115°C) to obtain dry powder, and then the dried powder is put into the atmosphere furnace, under a nitrogen protective atmosphere, From normal temperature, the temperature is raised to 350°C at a heating rate of 4°C/min and kept for 2 hours. Then, the temperature is continued to be raised to 710°C, kept for 10 hours, and then naturally cooled to obtain a sintered product. The sintered product is air-flow pulverized to obtain product two;
(3)将上述产物一、产物二按照1：2质量比进行混合，混合30min后得到最终产物，即可制备得到Mn/Fe为6:4、D50为1.21um、碳含量为1.478％、Ti含量为1562ppm、Mg含量为854ppm的磷酸铁锰锂正极材料MF64-C3。(3) Mix the above product one and two according to the mass ratio of 1:2. After mixing for 30 minutes, the final product is obtained. Mn/Fe is 6:4, D50 is 1.21um, carbon content is 1.478%, Ti Lithium iron manganese phosphate cathode material MF64-C3 with a content of 1562ppm and a Mg content of 854ppm.
试验例Test example
将实施例和对比例制得的磷酸铁锰锂材料按照正极材料粉体：导电剂(SP)：胶粘剂(PVDF)为90：5：5的比例调浆；将调好的浆料进行涂布、冲片、烘干。以金属锂片作为负极材料，用聚丙烯微孔薄膜作为隔膜，用电解液将他们装配成电池。电池密封后静止2小时后进行测试。将扣式半电池在蓝电测试柜上进行测试，测试电压范围为2V～4.3V，循环倍率1C循环，并测试材料压实密度、电阻率等理化指标，结果如表1所示。The lithium iron manganese phosphate material prepared in the Examples and Comparative Examples is slurried according to the ratio of cathode material powder: conductive agent (SP): adhesive (PVDF) of 90:5:5; the adjusted slurry is coated , develop and dry. Metal lithium sheets are used as negative electrode materials, polypropylene microporous films are used as separators, and electrolytes are used to assemble them into batteries. After the battery is sealed, it is tested after resting for 2 hours. The button half-cell was tested on the blue battery test cabinet. The test voltage range was 2V ~ 4.3V, the cycle rate was 1C cycle, and the physical and chemical indicators such as material compaction density and resistivity were tested. The results are shown in Table 1.
表1Table 1
Figure PCTCN2022119991-appb-000001
Figure PCTCN2022119991-appb-000001
Figure PCTCN2022119991-appb-000002
Figure PCTCN2022119991-appb-000002
从表1的结果可见，采用本发明工艺路线合成的材料，在材料的压实密度、扣电容量、粉末电阻率、放电中值电压上均存在较大的优势。对比例1和对比例2都只用了单一Mn/Fe比例的前驱体，相应性能没有得到改善，如对比例1的Mn含量居多，导电性能相对较差，对比例2的Fe含量居多，中值电压较低，而实施例虽然Mn/Fe比例与对比例一样，但实施例通过设计不同Mn/Fe元素的前驱体、同时控制不同前驱体的粒度，两者共同作用实现性能的综合提升。对比例3采用大小颗粒分开粉碎，再进行混合，气流粉碎过程中对碳包覆有一定的破坏效果，进行固相混合后，导致材料出现碳分层现象，会使材料粉末的电阻率出现明显升高，此外，由于固相混合天然存在均一性差的问题，会导致材料大小颗粒不均匀，从而降低材料的压实密度。It can be seen from the results in Table 1 that the materials synthesized using the process route of the present invention have great advantages in terms of material compaction density, capacitance capacity, powder resistivity, and discharge median voltage. Both Comparative Example 1 and Comparative Example 2 only used a single Mn/Fe ratio precursor, and the corresponding properties were not improved. For example, Comparative Example 1 had a high Mn content and relatively poor electrical conductivity, while Comparative Example 2 had a high Fe content and medium The value voltage is lower. Although the Mn/Fe ratio in the embodiment is the same as the comparative example, the embodiment achieves comprehensive improvement in performance by designing precursors of different Mn/Fe elements and controlling the particle sizes of different precursors at the same time. In Comparative Example 3, large and small particles are separately pulverized and then mixed. The air flow pulverization process has a certain destructive effect on the carbon coating. After solid-phase mixing, the material will suffer from carbon stratification, which will cause the resistivity of the material powder to appear significantly. In addition, due to the inherent problem of poor uniformity in solid phase mixing, it will lead to uneven particle size of the material, thereby reducing the compacted density of the material.
上面结合附图对本发明实施例作了详细说明，但是本发明不限于上述实施例，在所属技术领域普通技术人员所具备的知识范围内，还可以在不脱离本发明宗旨的前提下作出各种变化。此外，在不冲突的情况下，本发明的实施例及实施例中的特征可以相互组合。The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various modifications can be made without departing from the purpose of the present invention. Variety. In addition, the embodiments of the present invention and the features in the embodiments may be combined with each other without conflict.

Claims (10)

  1. 一种磷酸锰铁锂的制备方法，其特征在于，包括以下步骤：A method for preparing lithium iron manganese phosphate, which is characterized by comprising the following steps:
    S1：设计不同锰、铁元素配比，按以下方法分别制备至少一种高锰低铁型磷酸锰铁和至少一种高铁低锰型磷酸锰铁：将锰源、铁源、磷源、还原剂和水混合进行沉淀反应，所得沉淀物进行热处理，即得磷酸锰铁；其中所述高锰低铁型磷酸锰铁在所述沉淀反应时还加入第一掺杂剂；S1: Design different ratios of manganese and iron elements, and prepare at least one high-manganese and low-iron ferromanganese phosphate and at least one high-iron and low-manganese ferromanganese phosphate according to the following methods: combine manganese source, iron source, phosphorus source, and reduce The agent and water are mixed to perform a precipitation reaction, and the resulting precipitate is heat-treated to obtain ferromanganese phosphate; wherein the high-manganese low-iron type ferromanganese phosphate is also added with a first dopant during the precipitation reaction;
    S2：所述高锰低铁型磷酸锰铁和高铁低锰型磷酸锰铁按以下方法分别制成粒径D50为200-400nm的第一浆料和粒度D50为600-800nm的第二浆料：将磷酸锰铁、锂源、碳源、第二掺杂剂和水混合研磨，即得浆料；S2: The high-manganese low-iron type ferromanganese phosphate and the high-iron low-manganese type ferromanganese phosphate are respectively made into a first slurry with a particle size D50 of 200-400nm and a second slurry with a particle size D50 of 600-800nm according to the following methods. : Mix and grind ferromanganese phosphate, lithium source, carbon source, second dopant and water to obtain slurry;
    S3：将所述第一浆料和第二浆料混合，得到混合浆料，将所述混合浆料进行喷雾干燥，得到干燥粉体，将所述干燥粉体置于保护气氛下烧结，所得烧结产物经粉碎，即得所述磷酸锰铁锂。S3: Mix the first slurry and the second slurry to obtain a mixed slurry, spray-dry the mixed slurry to obtain dry powder, and sinter the dry powder under a protective atmosphere to obtain The sintered product is crushed to obtain the lithium iron manganese phosphate.
  2. 根据权利要求1所述的制备方法，其特征在于，步骤S1中，所述高锰低铁型磷酸锰铁的Mn/Fe元素摩尔比为(1-a):a，0.2≤a≤0.45；所述高铁低锰型磷酸锰铁的Mn/Fe元素摩尔比为(1-b):b，0.55≤b≤0.8。The preparation method according to claim 1, characterized in that, in step S1, the Mn/Fe element molar ratio of the high-manganese low-iron ferromanganese phosphate is (1-a): a, 0.2≤a≤0.45; The Mn/Fe element molar ratio of the high-iron low-manganese ferromanganese phosphate is (1-b):b, 0.55≤b≤0.8.
  3. 根据权利要求1所述的制备方法，其特征在于，步骤S1中，所述第一掺杂剂为氢氧化镁、硫酸镁或硝酸镁中的至少一种。The preparation method according to claim 1, wherein in step S1, the first dopant is at least one of magnesium hydroxide, magnesium sulfate or magnesium nitrate.
  4. 根据权利要求1所述的制备方法，其特征在于，步骤S1中，所述还原剂为草酸或抗坏血酸中的至少一种。The preparation method according to claim 1, characterized in that in step S1, the reducing agent is at least one of oxalic acid or ascorbic acid.
  5. 根据权利要求1所述的制备方法，其特征在于，步骤S2中，所述碳源为葡萄糖、聚乙二醇、蔗糖、淀粉或纤维素中的至少一种。The preparation method according to claim 1, characterized in that in step S2, the carbon source is at least one of glucose, polyethylene glycol, sucrose, starch or cellulose.
  6. 根据权利要求1所述的制备方法，其特征在于，步骤S2中，所述第二掺杂剂为铝化合物、钛化合物、铌化合物或锆化合物中的至少一种。The preparation method according to claim 1, wherein in step S2, the second dopant is at least one of an aluminum compound, a titanium compound, a niobium compound or a zirconium compound.
  7. 根据权利要求1所述的制备方法，其特征在于，步骤S3中，所述混合浆料中Mn/Fe元素摩尔比为0.25-4。The preparation method according to claim 1, characterized in that in step S3, the Mn/Fe element molar ratio in the mixed slurry is 0.25-4.
  8. 根据权利要求1所述的制备方法，其特征在于，步骤S3中，所述喷雾干燥的进风温度为220-260℃，出风温度为105-115℃。The preparation method according to claim 1, characterized in that in step S3, the inlet air temperature of the spray drying is 220-260°C, and the air outlet temperature is 105-115°C.
  9. 根据权利要求1所述的制备方法，其特征在于，步骤S3中，所述磷酸锰铁锂的粒径D50为600-1500nm，压实密度为2.4-2.6g/cm 3。 The preparation method according to claim 1, characterized in that in step S3, the particle size D50 of the lithium iron manganese phosphate is 600-1500 nm, and the compacted density is 2.4-2.6g/cm 3 .
  10. 如权利要求1-9中任一项所述的制备方法在制备锂离子电池中的应用。Application of the preparation method according to any one of claims 1 to 9 in the preparation of lithium ion batteries.
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